Injuries to the kidney have shown a great increase in frequency during recent years and are now of relatively common occurrence. Severe injuries are of the utmost importance because they constitute a serious menace to life itself, and these traumas have consequently received the consideration due them. Mild injuries to the kidney are more important to the practitioner in view of their greater frequency—traumas which may not at the time appear as significant but which may lead to the invalidism of chronic or recurrent infection and in some instances to subsequent formation of stone.
The diagnosis in severe cases is not difficult, the syndrome of pain, hematuria and prostration after a blow to the loin giving a characteristic clinical picture. With mild traumas, however, it has been impossible to determine with certainty whether or not damage to the kidney has actually taken place. Many injuries diagnosed in the past as